Such plastically deformable implants are used, for example, in ophthalmology, in particular as vitreous body or lens replacement, and in dentistry, for example, for filling cavities left after tooth extraction in the jaw bone.
In addition, in plastic surgery, it is known to use deformable implants which, however, invariably comprise a cushion-like envelope and an implant material as a filler, thus providing a barrier with respect to the surrounding tissue and thereby ensuring biocompatibility.
For ophthalmological applications, fluorine-containing compounds in the form of readily moving liquids and preparations are known. In this field of application, the properties typical for fluorine-containing compounds, such as high density and low surface tension, are utilized. The partially fluorinated and perfluorinated compounds so far used, however, are single-phase liquids. As a result, varying material properties can be utilized only to the extent defined by the structure and the inherent properties of the chemical compounds used. Thus, with the conventionally known fluorine-containing ophthalmological preparations it is not possible to meet the frequently highly different and in part opposite requirements of the preparation with one single material component.
Thus, for example, during and after vitreoretinal interventions, a preparation is needed which has excellent tamponade properties and, at the same time, offers the possibility of an exchange of water-soluble substances, which cannot be simultaneously achieved with the well-known ophthalmological preparations since these do not mix with water. In addition, an attempt was made to avoid injury to the retina—which is observed during the ophthalmological application of perfluorocarbons and which is to be attributed to mechanical effects—by using substances with a lower density, such as those described in European Patent No. 563 446 B1 and German Patent Nos. DE 197 19 280 and DE 195 36 504 A1. Unfortunately, this entailed a simultaneous increase in the lipophilic properties of these compounds, which led to penetration. As a result, histological changes as well as side effects similar to those known from perfluorocarbons were observed.
In addition, in prior art, it has been known to use fluorine-containing gels of the class of fluorocarbon-water emulsions. Emulsions in the form of gels of this type and their possible applications in medicine and technology have been described, for example, in U.S. Pat. No. 5,573,757, in European Patent No. EP 0 340 079, and in International Patent No. WO 97/03644. These gels form polyaphron structures with a continuous minority phase and a discontinuous majority phase. During this process, the minority phase completely encapsulates the majority phase and thus determines the most important properties of the overall preparation. As known from prior art, a very specific working sequence must be followed in order to produce preparations with this type of structure. Furthermore, it is also known from prior art that in gels of this type, a destruction or liquefaction, for example, by means of heat or mechanical pressure, is irreversible, i.e., once a gel has been destroyed, its original gel structure cannot be restored. This has been described in articles published by M. P. Kraff and J. G. Riess in Angew. Chem. 106 (1994), p. 1146, and by H. Hoffmann and G. Ebert in Angew. Chem. 100 (1988), p. 933.
In addition, the fluorine-containing gels known from prior art have an affinity both to water and to body tissues. When such gels are used over long periods of time in aqueous media or in body tissue, this affinity to water and tissue leads to a liquefaction and destruction of the gels. This, together with the fact that the gel, once destroyed, cannot have its structure restored since the destruction is irreversible prevents the long-term use of this gel as an implant in body tissue.